Method of depositing thin film and method of manufacturing semiconductor device

• US 10,714,335 B2
• Filed: 04/10/2018
• Issued: 07/14/2020
• Est. Priority Date: 04/25/2017
• Status: Active Grant

• Current Assignee: ASM IP Holding B.V. (ASM International NV)
• Original Assignee: ASM IP Holding B.V. (ASM International NV)
• Inventors: Kim, Young Hoon, Han, Yong Gyu, Kim, Dae Youn, Yoo, Tae Hee, Lim, Wan Gyu, Yu, Jin Geun
• Primary Examiner(s): Kebede, Brook
• Application Number:
  US15/949,990
• Publication Number:
  US 20190115206A1
• Time in Patent Office: 826 Days
• Field of Search: 438446, 438703, 438791
• CPC Class Codes: C23C 16/345 Silicon nitride
• CPC Class Codes: C23C 16/45525 Atomic layer deposition [ALD]
• CPC Class Codes: C23C 16/45542 Plasma being used non-continuously during the ALD reactions
• CPC Class Codes: C23C 16/50 using electric discharges generation and control of plasma in discharge tubes for surface treatment H01J37/32, H01J37/34
• CPC Class Codes: H01L 21/02164 the material being a silicon oxide, e.g. SiO2
• CPC Class Codes: H01L 21/0217 the material being a silicon nitride not containing oxygen, e.g. SixNy or SixByNz H01L21/02126 and H01L21/0214 take precedence
• CPC Class Codes: H01L 21/02208 the precursor containing a compound comprising Si
• CPC Class Codes: H01L 21/02211 the compound being a silane, e.g. disilane, methylsilane or chlorosilane
• CPC Class Codes: H01L 21/02219 the compound comprising silicon and nitrogen
• CPC Class Codes: H01L 21/02274 in the presence of a plasma [PECVD]
• CPC Class Codes: H01L 21/0228 deposition by cyclic CVD, e.g. ALD, ALE, pulsed CVD
• CPC Class Codes: H01L 21/0332 characterised by their composition, e.g. multilayer masks, materials
• CPC Class Codes: H01L 21/0337 characterised by the process involved to create the mask, e.g. lift-off masks, sidewalls, or to modify the mask, e.g. pre-treatment, post-treatment
• CPC Class Codes: H01L 21/0338 Process specially adapted to improve the resolution of the mask
• CPC Class Codes: H01L 21/31111 by chemical means
• CPC Class Codes: H01L 21/31144 using masks

Abstract

Provided is a method of depositing a thin film on a pattern structure of a semiconductor substrate, the method including (a) supplying a source gas; (b) supplying a reactive gas; and (c) supplying plasma, wherein the steps (a), (b), and (c) are sequentially repeated on the semiconductor substrate within a reaction space until a desired thickness is obtained, and a frequency of the plasma is a high frequency of 60 MHz or greater.

Claims

1. A method of depositing a thin film on a pattern structure of a semiconductor substrate, the method comprising:

(a) supplying a source gas;

(b) supplying a reactive gas; and

(c) supplying plasma,

wherein the steps (a), (b), and (c) are sequentially repeated on the semiconductor substrate within a reaction space until a desired thickness is obtained, and a frequency of the plasma is a frequency of at least 60 MHz or greater,

wherein the pattern structure has a top surface, a bottom surface, and a side surface that connects the top surface with the bottom surface, a length of the side surface being greater than a width of the top surface and a width of the bottom surface,

the frequency of at least 60 MHz or greater is used to form the thin film having a uniform physical thickness and uniform chemical characteristics on an entire area of the top surface, the bottom surface, and the side surface of the pattern structure,

wherein, in the step (c), the plasma is supplied in a pulse mode, and an overall amount of plasma supplied is equal to an amount of the plasma supplied in a continuous mode, and

wherein at least one material is activated during a PEALD process and has reactivity with the pattern structure, so that at least a portion of the pattern structure is damaged during the step (c), generating a difference between critical dimensions (CDs) of an inner space and an outer space of the pattern structure,

wherein, in order to decrease loss of the pattern structure, the plasma is supplied onto the semiconductor substrate at a duty ratio of 50%, and the plasma is supplied at a power amount twice that of the plasma supplied in the continuous mode.

2. The method of claim 1, wherein a purge gas is continuously supplied in all of the steps (a), (b), and (c).

3. The method of claim 2, wherein the reactive gas is continuously supplied in all of the steps (a), (b), and (c), the reactive gas comprises a constituent of the thin film, and, when the reactive gas is not activated by the plasma, the reactive gas is inert to the source gas.

4. The method of claim 3, wherein, after the step (c), the purge gas and the reactive gas are further supplied.

5. The method of claim 1, wherein, during the step (c), at least a portion of the pattern structure is removed.

6. The method of claim 1, wherein, in the step (c), the plasma is supplied in a continuous mode.

7. The method of claim 1, wherein the plasma is supplied at a power in a range of 200 watts to 2,000 watts.

8. The method of claim 1, further comprising wet-etching the thin film deposited on the pattern structure.

9. The method of claim 1, wherein a ratio between wet etch rates (WERs) of portions of the thin film respectively deposited on a sidewall and a top of the pattern structure is 1.5 or less.

10. The method of claim 1, wherein the pattern structure of the semiconductor substrate comprises a hardmask.

11. A thin film deposition method comprising:

preparing a substrate comprising a thin film and a first mask pattern formed on the thin film; and

forming a second mask layer on an exposed surface of the thin film and on the first mask pattern,

wherein

the forming of the second mask layer is performed by applying plasma at a frequency of 60 MHz or greater by using a plasma-enhanced atomic layer deposition (PEALD) process, and

the plasma is discontinuously applied,

wherein the first mask pattern has a top surface, a bottom surface, and a side surface that connects the top surface with the bottom surface, a length of the side surface being greater than a width of the top surface and a width of the bottom surface,

wherein the frequency of 60 MHz or greater is used to form the second mask layer having a uniform physical thickness and uniform chemical characteristics on an entire area of the top surface, the bottom surface, and the side surface of the first mask pattern,

wherein, during the applying plasma, the plasma is supplied in a pulse mode, and an overall amount of plasma supplied in the pulse mode is equal to an amount of the plasma supplied in a continuous mode, and

wherein at least one of materials used during the PEALD process has reactivity with the first mask pattern, so that at least a portion of the first mask pattern is damaged during the applying plasma in the forming of the second mask layer, generating a difference between critical dimensions (CDs) of an inner space and an outer space of the first mask pattern.

12. The thin film deposition method of claim 11, wherein

the plasma is discontinuously applied during all of a plurality of sub-periods, and

during each of the plurality of sub-periods, plasma is applied at a duty ratio of 50% or less.

13. A method of manufacturing a semiconductor device, the method comprising:

forming a first layer on a substrate;

forming a second layer on the first layer;

exposing at least a portion of the first layer by patterning the second layer;

forming a third layer on an exposed surface of the first layer and on the second layer, wherein the forming of the third layer is performed by applying plasma at a frequency of 60 MHz or greater by using a plasma-enhanced atomic layer deposition (PEALD) process; and

forming a spacer pattern by removing at least a portion of the third layer,

wherein the patterned second layer has a top surface, a bottom surface, and a side surface that connects the top surface with the bottom surface, a length of the side surface being greater than a width of the top surface and a width of the bottom surface,

the frequency of 60 MHz or greater is used to form the third layer having a uniform physical thickness and uniform chemical characteristics on an entire area of the top surface, the bottom surface, and the side surface of the patterned second layer,

wherein, during the applying plasma, the plasma is supplied in a pulse mode, and an overall amount of plasma supplied is equal to an amount of the plasma supplied in a continuous mode,

wherein at least one of materials used during the PEALD process has reactivity with the patterned second layer, so that at least a portion of the patterned second layer is damaged during the applying plasma in the forming of the third layer, generating a difference between critical dimensions (CDs) of an inner space and an outer space of the patterned second layer, and

wherein, in order to decrease loss of the patterned second layer that is below the third layer, the plasma is supplied onto the substrate at a duty ratio of 50% or less than 50%, and the plasma is supplied at a power amount twice or larger than twice that of the plasma supplied in the continuous mode.

14. The method of claim 13, further comprising:

removing the second layer; and

etching the first layer by using the spacer pattern as a mask.

15. The method of claim 13, wherein the plasma having the frequency of 60 MHz or greater is discontinuously applied during a plurality of sub-periods.